A federal judge, invoking baseball's long-discredited but legally entrenched exemption from antitrust laws, has batted down San Jose's attempt to lift the major leagues' blockade on the Oakland A's move to the South Bay.

But U.S. District Judge Ronald Whyte's ruling Friday kept part of San Jose's suit alive, a claim that Major League Baseball interfered with its contract with the A's by delaying a vote by club owners on relocating the team. That portion of the suit seeks only monetary damages, but a lawyer for the city said it might give San Jose leverage to finally bring Commissioner Bud Selig to the table to negotiate a move.

San Jose will gain access to MLB's books in pretrial proceedings and should be able to learn why a committee appointed by Selig in March 2009 to review the A's bid to move to the city has yet to act, said attorney Phil Gregory.

He said San Jose and its lawyers haven't decided yet whether to appeal Whyte's dismissal of the main part of the suit, which seeks to move the A's, or to press ahead with the contract claim in hopes of a settlement that would accomplish the same thing.

Selig's office issued a statement saying the major leagues were "pleased that the court dismissed the heart of San Jose's action and confirmed that MLB has the legal right to make decisions about the relocation of its member clubs."

San Jose sued the major leagues in June to challenge rules that require approval from three-fourths of the teams for a franchise to move within another team's territory. The San Francisco Giants, whose territorial rights include Santa Clara County, have objected to the move.

The A's and San Jose have agreed on a nearly $7 million contract for a new stadium near the city's downtown Diridon train station. A's owners Lew Wolff and John Fisher have been trying for years to move the team out of its aging Oakland stadium.

The main obstacle is baseball's exemption, unique among professional sports, from antitrust laws that limit the power of monopolies and allow a would-be competitor to challenge unreasonable restraints of trade.

The Supreme Court ruled in 1922 that the major leagues were not engaged in interstate commerce and therefore were not subject to antitrust laws. Rulings in 1953 and 1972 disavowed the rationale of the earlier decision but reaffirmed its conclusion on the grounds that Congress had not acted to change the law.

In his ruling, Whyte repeated what he had said a week earlier at a hearing in his San Jose courtroom: that the antitrust exemption is obsolete and indefensible, but can be revoked only by Congress or the high court.

"The exemption is an aberration that makes little sense given the heavily interstate nature of the business of baseball today," Whyte said.

He rejected San Jose's argument that the exemption had been narrowed by later rulings and no longer applied to franchise relocations.

"The alleged interference with a baseball club's relocation efforts presents an issue of league structure that is integral to the business of baseball, and thus falls squarely within the (antitrust) exemption," the judge said.

He added, however, that San Jose could still try to prove that the major leagues interfered with the city's contract with the A's by first asking the city to hold off on approving the move, and then putting off a vote of team owners on relocation.

While undecided on an appeal, San Jose's lawyers said they were confident that the Supreme Court would be willing to reconsider and overturn baseball's antitrust exemption.

"I find it hard to believe Major League Baseball is not subject to the same antitrust rules that apply to all other sports," said attorney Joseph Cotchett.

William Gould, a Stanford law professor who has written extensively on sports law, disagreed.

"I don't think the prospects are good" for an appeal, he said. "This court, in countless ways, is all about the business of protecting business."